The hydratable, polymer matrix films which comprise low solubility polymer additives and are produced free of low solubility flavorants free of low solubility flavorants are combined with dentifrice base that comprises low solubility flavorant which migrates from the dentifrice base into the hydratable, polymer matrix films to form a dentifrice that comprises hydratable, polymer matrix films which include low solubility flavorants.
Liquid, gel and semi-solid oral care products which comprise hydratable, polymer matrix films containing low solubility flavorants such as menthol are known. Hydratable, polymer matrix film containing low solubility flavorants such as menthol are prepared and added into toothpaste to generate an aesthetic effect as well as to provide the benefit of a flavor and/or cooling sensation or signal. The hydratable, polymer matrix film, typically in the form of flakes or small sized pieces cut from larger manufactured films, is maintained in the product when stored. Upon use, the films typically degrade by chemical or physical disruption, thereby releasing the active or functional material into the surrounding environment. In this manner, the films provide an opportunity for localized release of a high concentration of active materials, such as for example zinc oxide, near a target surface. In addition, low solubility flavorant in the film is also released. The low solubility flavorants such as menthol in the films provide an extended flavor experience to the user compared to that which occurs when compositions in which the flavor is only in the toothpaste base are used. By including flavorants in the films, flavor may be released from films during and immediately after use, providing a flavor experience that continues after performance of the oral care process such as brushing or rinsing is completed. This extended experience can be pleasing.
Conventional methods of manufacturing hydratable, polymer matrix films that contain low solubility flavorants such as menthol comprise the step of incorporating menthol into the slurry that is then used to form the film. The low solubility flavorant is thereby dispersed throughout the slurry which is used to make the film. After the film is formed, it is typically often cut into flakes or pieces, and introduced into the toothpaste base. The step of adding relatively insoluble flavorant into the slurry used to manufacture the hydratable, polymer matrix films typically requires the use of solvents such as ethanol. When making the films, the ethanol is typically removed using heat which causes the ethanol to evaporate. The low solubility flavorants are lost as a result of evaporation of the ethanol solvent. For examples, 50% of menthol in a slurry formula is lost with the solvent when the ethanol evaporates. Moreover, the evaporated ethanol creates a safety concern in the manufacturing facility. Accordingly, introduction of low solubility flavorants into the film during its manufacture is inefficient, which leads to in additional manufacturing costs, and creates conditions which must be managed to avoid safety problems.
There is a need for improved methods of manufacturing liquid, gel and semi-solid oral care products which comprise hydrophilic films containing menthol.